Test apparatus, test set-up and method for testing a device under test

Abstract

A test apparatus (12) for testing a device under test (14) has a first and a second signal generator (18, 20), a receiver (22), a triplexer (24), a transfer switch (26), and a measurement port (28). The first signal generator (18), the second signal generator (20) and the receiver (22) are each connected to one of a first, second, and third band port (42, 44, 46) of the triplexer (24), partly via the associated transfer switch (26). The associated transfer switch (26) is configured to swap the connection of the first signal generator (18), of the second signal generator (20), and / or of the receiver (22) to one of the first, second, and third band port (42, 44, 46). Further, a test setup (10) and a method are shown.

Description

[0001] Test apparatus, test set-up and method for testing a device under test Technical Field

[0002] The invention relates to a test apparatus for testing a device under test, a test set-up as well as a method for testing a device under test.

[0003] Background

[0004] Equipment used in mobile communication base stations, such as antennas, filters, feeder cables, and the like, must meet strict passive intermodulation (PIM) requirements. To ensure this, the components are usually fully tested after production which is a very time-consuming process.

[0005] US 9 455 792 Bl discloses a test apparatus for performing PIM measurements. Known test apparatuses have a very small bandwidth so that testing and in particular PIM measurements of equipment that have a plurality of channels, such as antennas, is very tedious and time-consuming. Summary

[0006] It is therefore the object of the invention to provide a test apparatus, a test setup, and a method that allow testing of a device under test quicker and more efficiently.

[0007] For this purpose, a test apparatus for testing, in particular for performing PIM measurements, of a device under test, in particular an antenna under test, is provided. The test apparatus comprises at least one first signal generator, at least one second signal generator, at least one receiver, at least one triplexer, at least one transfer switch, and at least one measurement port for connecting the test apparatus to the device under test. The at least one triplexer is associated with one of the at least one transfer switch, with one of the at least one first signal generator, with one of the at least one second signal generator, with one of the at least one receiver, and with one of the at least one measurement port. The at least one transfer switch comprises a first switch port, a second switch port, a third switch port, and a fourth switch port, and the triplexer comprises a common port connected to the first associated measurement port, a first band port, a second band port, and a third band port. The associated first signal generator, the associated second signal generator and the associated receiver are each connected to one of the first band port, the second band port and the third band port of the associated triplexer, partly via the associated transfer switch, and the associated transfer switch is configured to swap the connection of the associated first signal generator, of the associated second signal generator and / or of the associated receiver to one of the first band port, the second band port and / or the third band port.

[0008] By using a triplexer that is connected to a transfer switch, capable of swapping, i.e. exchanging the connection of the components to the ports of the triplexer, it is possible to increase the bandwidth of the test apparatus as the test apparatus may be used to test the PIM at different frequency bands, e.g. different frequency bands corresponding to the different frequency bands of the several band ports of the triplexer. Further, the use of the triplexer allows to sweep across a very broad frequency range, further increasing the bandwidth.

[0009] Furthermore, the loss in the test apparatus is reduced, for example by about 3dB, as compared to known test apparatuses using a combiner and a duplexer.

[0010] The first and second signal generators may be separate hardware signal generators or logical signal generators provided by the same hardware.

[0011] It is conceivable that the first signal generator, the second signal generator and / or the receiver are part of a single device, for example a vector network analyzer.

[0012] For simplification, within this disclosure "connected to" or the like is to be understood as "electrically connected to", thus allowing transfer of RF signals.

[0013] The transfer switch may be a single device or a combination of connected switches providing the described switching functionality. The transfer switch may be separate or combined with another component.

[0014] In an embodiment, the transfer switch has a first switching position and a second switching position, wherein, in the first switching position, the first switch port is connected to the second switch port, and the third switch port is connected to the fourth switch port, and in the second switching position, the first switch port is connected to the fourth switch port and the second switch port is connected to the third switch port. This way, the connections of two components, i.e. signal generators or receiver, may be swapped.

[0015] For example, the first band port is connected to the fourth switch port of the associated transfer switch, the second band port is connected to the associated first signal generator, the third band port is connected to the second switch port of the associated transfer switch, and the first switch port of the associated transfer switch is connected to the associated receiver, and the third switch port of the associated transfer switch is connected to the associated second signal generator. By virtue of this setup, the band ports and thus the frequency bands the second signal generator and the receiver are connected to can be swapped by the switch, allowing measurements in both frequency bands.

[0016] In an embodiment, the first band port is a low -band port, the second band port is a mid-band port and the third band port is a high-band port, allowing to swap the receiver and the second signal generator around the frequency band of the first signal generator.

[0017] In particular, the frequency band of the low-band port lies below the frequency bands of the mid-band and high-band ports, the frequency band of the mid-band port lies between the frequency bands of the low-band and high- band ports, and / or the frequency band of the high-band port lies above the frequency bands of the low-band and mid-band port.

[0018] In an aspect, the second band port has a bandwidth being less than the bandwidth of the first band port and of the bandwidth of the third band port, in particular less than fifth, more particularly less than one tenth of the bandwidth of the first band port and of the bandwidth of the third band port. This allows frequency sweeps and measurements over very large bandwidths.

[0019] For example, the second band port has a bandwidth being less or equal to 20 MHz, in particular less or equal to 5 MHz, minimizing the bandwidth in which no measurement is performed.

[0020] For maximizing the bandwidth in which measurements may be performed, the first band port may have a bandwidth being greater or equal to 250 MHz, in particular greater or equal to 400 MHz, and / or the third band port may have a bandwidth being greater or equal to 250 MHz, in particular greater or equal to 400 MHz.

[0021] In an embodiment, the test apparatus comprises a plurality of the measurement ports, in particular 4, 8, 12, 16, 18 or 32 measurement ports, a plurality of the triplexers, a plurality of the transfer switches, and a plurality of the receivers, wherein each of more than one of or each of all of the plurality of the measurement ports is associated with one of the plurality of the triplexers, with one of the plurality of transfer switches and with one of the plurality of receivers, allowing parallel measurements of signal input at the different measurement ports.

[0022] The triplexer, transfer switch and receiver associated with the same measurement port may be connected as described above.

[0023] For reducing the components needed, the at least one first signal generator and / or the at least one second signal generator may be connected to more than one measurement port via the transfer switches and triplexers associated with the respective measurement ports, in particular using a power splitter.

[0024] In an aspect, the test apparatus comprises at least one power splitter and a plurality of power amplifiers, wherein the at least one first signal generator and / or the at least one second signal generator is connected to more than one of the plurality of power amplifiers via a respective power splitter, allowing to have signal generators with less output power.

[0025] For each of the measurement ports a power amplifier is provided, wherein the power amplifier receives and amplifies signals from the associated first signal generator and outputs the amplified signal of the first signal generator, in particular to the second band port of the associated triplexer, and wherein the respective power amplifier receives and amplifies signals from the associated second signal generator and outputs the amplified signal of the second signal generator, in particular to the third switch port of the associated transfer switch, allowing to reduce the number of power amplifiers.

[0026] The power amplifier is also associated with the respective measurement port and its associated components. In particular, one power amplifier is provided for each measurement port.

[0027] In an aspect, the test apparatus comprises a control unit, wherein the control unit is configured to control the switching position of the transfer switch, the at least one receiver, the at least one first signal generator and the at least one second signal generator, allowing for automated measurements over the entire measurement frequency range of the test apparatus.

[0028] The control unit may be a single device or distributed across several devices.

[0029] To improve the sample rate and thus the measurement speed, the control unit may be configured to synchronize the at least one first signal generator and the at least one second signal generator, in particular using TTL (Transistortransistor logic) signals and / or a second realtime channel with reduced or no protocol overhead.

[0030] For above mentioned purpose, further a test setup is provided, the test setup comprising a device under test and a test apparatus as described above, wherein the device under test is connected to the at least one measurement port.

[0031] The features and advantages described with respect to the test apparatus also apply to the test setup and vice versa.

[0032] The device under test is in particular an antenna under test or components of an antenna.

[0033] In an embodiment, the device under test has a plurality of device ports and the test apparatus comprises a plurality of the measurement ports, in particular wherein each of the device ports of the device under test is connected to one of the measurement ports of the test apparatus and / or each of the measurement ports of the test apparatus is connected to one of the device ports of the device under test. This way, parallel measurements of several or all of the channels of the device under test are possible.

[0034] For example, the device has 4, 8, 12, 16, 18, or 32 channels and 4, 8, 12, 16, 18, or 32 device ports, respectively.

[0035] For above mentioned purpose, further a method is provided for testing, in particular for performing PIM measurements, of a device under test, in particular an antenna under test, using a test apparatus as described above and / or a test setup as described above. The method comprises:

[0036] - generating a first carrier signal by the at least one first signal generator and applying the first carrier signal to the second band port of the associated triplexer,

[0037] - generating a second carrier signal by the at least one second signal generator and applying the second carrier signal to the third switch port of the associated transfer switch,

[0038] - setting the associated transfer switch in the first switching position or the second switching position,

[0039] - sweeping the frequency of the second carrier signal in a frequency range being the entire frequency band or part of the frequency band of the first band port or the third band port, respectively, of the associated triplexer, and

[0040] - measuring the signal input at the measurement port by the receiver.

[0041] The features and advantages described with respect to the test apparatus and / or the test setup also apply to the method and vice versa. Based on the measured signal with respect to the first and second carrier signals the presence and optionally the location of PIM is determined, in particular by the control unit.

[0042] For example, the first carrier signal has a frequency within the frequency band of the second band port and / or the frequency of the first carrier signal is kept constant.

[0043] In order to increase the measurement bandwidth further, after sweeping the frequency of the second carrier signal in a transmit frequency range being the entire frequency band or part of the frequency band of the first band port or the third band port, respectively, of the associated triplexer, the associated transfer switch may be switched from the first switching position to the second switching position or from the second switching position to the first switching position, respectively. The frequency of the second carrier signal may be swept in a transmit frequency range being the entire frequency band or part of the frequency band of the third band port or the first band port, respectively, of the associated triplexer, and the signal input at the measurement port may be measured by the receiver.

[0044] In an aspect, the generation of the first carrier signal and of the second carrier signal as well as the measurement of the signal input is performed for more than one, in particular all of the measurement ports of the test apparatus simultaneously, further reducing measurement time.

[0045] Brief Description of the Drawings

[0046] Further features and advantages will be apparent from the following description as well as the accompanying drawings, to which reference is made. In the drawings: Figure 1 shows a test set-up according to an embodiment of the invention comprising a test apparatus according to an embodiment of the invention,

[0047] Figure 2 shows a schematic flowcharts of a method according to an embodiment of the invention,

[0048] Figures 3, 4 show illustrations of the frequency bands and signals used during the method according to Figure 2 in the first and second switching position of the transfer switch, respectively, and

[0049] Figure 5 shows a test setup as well as a test apparatus according to a second embodiment of the invention.

[0050] Detailed Description

[0051] Figure 1 shows schematically an embodiment of a test setup 10. The test setup 10 comprises a test apparatus 12 and a device under test 14, which is an antenna under test in the shown embodiment.

[0052] The device under test 14 is in particular arranged in an anechoic chamber or below an absorber sky.

[0053] The device under test 14 is, for example, a passive multi-channel antenna for a mobile communication base station or a component of an antenna.

[0054] The device under test 14 may be a Multiple -Input and Multiple-Output (MIMO) antenna and / or a directional antenna.

[0055] A channel of the antenna under test is, for example, regarded as a signal path through which cable-bound radiofrequency signals (RF-signals) are received and emitted as electromagnetic radiation or vice versa. For example, one channel includes a device port 16 and an array of radiators.

[0056] The device under test 14 comprises at least one channel, as indicated in Figure 1, thus at least one device port 16 and one array of radiators. The device under test 14 may also comprise a plurality of channels, for example, 4, 8, 12, 16, 18 or 32 channels and the same number of device ports 16.

[0057] The test apparatus 12 is configured for testing the device under test 14, in particular for performing PIM (passive intermodulation) measurements.

[0058] The test apparatus 12 comprises a first signal generator 18, a second signal generator 20, a receiver 22, a triplexer 24, a transfer switch 26, a measurement port 28 and a control unit 30.

[0059] The first signal generator 18, the second signal generator 20 and the receiver 22 are connected to the measurement port 28 via the triplexer 24 and partly, here in the case of the second signal generator 20 and the receiver 22, also via the transfer switch 26.

[0060] Within this disclosure, connected is to be understood as electrically connected allowing the transfer of radiofrequency signals (RF signals). The connection is in particular formed by a conductor, i.e. it is a galvanic connection.

[0061] For example, the first signal generator 18, the second signal generator 20, the receiver 22, the triplexer 24, the transfer switch 26, and the measurement port 28 are capable of generating, receiving, transmitting, and / or switching RF signals.

[0062] The transfer switch 26 has a first switch port 32, a second switch port 34, a third switch port 36, and a fourth switch port 38.

[0063] The transfer switch 26 is configured to assume two switching positions. In the first switching position the first switch port 32 is connected to the second switch port 34 and the third switch port 36 is connected to the fourth switch port 38. In the second switching position, the first switch port 32 is connected to the fourth switch port 38, and the second switch port 34 is connected to the third switch port 36.

[0064] The transfer switch 26 is controlled by the control unit 30, i.e. the control unit 30 may switch the transfer switch 26 from the first switching position to the second switching position and back. To this end, the control unit 30 and the transfer switch 26 have a communication and / or control connection, in particular a wired connection.

[0065] The control unit 30 may be a single device or distributed across several devices.

[0066] The triplexer 24 comprises a common port 40, a first band port 42, a second band port 44, and a third band port 46.

[0067] The first band port 42, the second band port 44, and the third band port 46 are multiplexed into the common port 40, as per se known in the art. The band ports 42, 44, 46 have disjoint frequency bands. For example, the first band port 42 is a low-band port, the second band port 44 is a mid-band port and the third band port 46 is a high-band port.

[0068] The frequency band of the low-band port lies below the frequency bands of the mid-band and high-band ports. The frequency band of the mid-band port lies between the frequency bands of the low-band and high-band ports. The frequency band of the high-band port lies above the frequency bands of the low-band and the mid-band port.

[0069] Further, the band ports 42, 44, and 46 may be configured (i.e. the triplexer 24 is configured accordingly) so that the second band port 44 has a bandwidth being less than the bandwidth of the first band port 42. The bandwidth of the second band port 44 is also smaller than the bandwidth of the third band port 46. For example, the bandwidth of the second band port 44 is less than fifth, in particular less than one tenth of each of the bandwidth of the first band port 42 and of the second band port 46.

[0070] For example, the second band port 44 has a bandwidth being less than or equal to 20 MHz, in particular less than or equal to 5 MHz, whereas the first band port 42 and also the third band port 46 may have a bandwidth being greater or equal to 250 MHz, in particular greater or equal to 400 MHz.

[0071] The triplexer 24 is associated with the measurement port 28 and, as such, the common port 40 of the triplexer 24 is connected to the measurement port 28.

[0072] The measurement port 28 is, in turn, connected to the device port 16 of the device under test 14.

[0073] The triplexer 24 is also associated with the first signal generator 18 and the transfer switch 26. The transfer switch 26 is, in turn, associated with the second signal generator 20 and the receiver 22.

[0074] Thus, the first signal generator 18, the second signal generator 20, the receiver 22, the triplexer 24 and the transfer switch 26 are associated with one another and with the measurement port 28.

[0075] The triplexer 24 is connected to the first signal generator 18 and the transfer switch 26.

[0076] More precisely, the first signal generator 18 is connected to the second band port 44 of the triplexer 24.

[0077] In the shown embodiment, a power amplifier 48 of the test apparatus 12 is provided between the first signal generator 18 and the triplexer 24, amplifying the RF signals generated by the first signal generator 18.

[0078] The power amplifier 48 and / or the first signal generator 18 may also be controlled by the control unit 30 and, to this end, they have a communication and / or control connection, in particular a wired connection to the control unit 30.

[0079] Also the power amplifier 48 is associated with the measurement port 28 and the other components associated with the measurement port 28.

[0080] Of the triplexer 24, the first band port 42 and the third band port 46 are connected to the transfer switch 26. More precisely, the first band port 42 is connected to the fourth switch port 38 of the transfer switch 26 and the third band port 46 of the triplexer 24 is connected to the second switch port 34 of the transfer switch 26.

[0081] Of the transfer switch 26, the first switch port is connected to the receiver 22.

[0082] Between the receiver 22 and the transfer switch 26, an amplifier 50, in particular a low noise amplifier, may be provided, amplifying the signals input at the measurement port 28, i.e. received from the device under test 14.

[0083] Similarly to the power amplifier 48, the amplifier 50 may be controlled by the control unit 30 and may have a communication and / or control connection to the control unit 30.

[0084] The receiver 22 may be a single port receiver or a measurement port of a multiport receiver device.

[0085] The control unit 30 may also control the receiver 22, in particular, receive the measurement results from the receiver 22. To this end, a communication and / or control connection between the receiver 22 and the control unit 30 is provided.

[0086] The third switch port 36 of the transfer switch 26 is connected to the second signal generator 20. Similarly, to the first signal generator 18, the second signal generator 20 is connected to the transfer switch 26 via a power amplifier 48. In the shown embodiment, the same power amplifier 48 as for the first signal generator 18 may be used.

[0087] It is conceivable that two distinct power amplifiers 48 are provided, one for the first signal generator 18 and one for the second signal generator 20.

[0088] In the shown embodiment, the first signal generator 18 and the second signal generator 20 are separate and distinct hardware, i.e. hardware signal generators. It is also conceivable that the first signal generator 18 and the second signal generator 20 are logical signal generators provided by the same piece of hardware.

[0089] For testing the device under test 14, the test apparatus 12 and the entire test setup 10 is configured to carry out a method as, for example, shown in Figure 2.

[0090] In particular, the control unit 30 controls the components to perform the method accordingly.

[0091] At SI, a first carrier signal is generated by the first signal generator 18, wherein the first carrier signal has a frequency fi within the frequency band of the second band port 44 of the triplexer 24.

[0092] Further, the frequency fi of the first carrier signal is kept constant.

[0093] The first carrier signal is then, via the power amplifier 48 applied to the second band port 44 of the associated triplexer 24.

[0094] Further, at S2, in particular simultaneously to SI, a second carrier signal is generated by the second signal generator 20. The second carrier signal has a frequency within the frequency band of the first band port 42. The frequency of the second carrier signal is further not constant.

[0095] At S3, in particular simultaneously to or before SI and / or S2, the transfer switch 26 is set in the first switching position, i.e. the transfer switch 26 is kept in the first switching position or it is switched from the second switching position to the first switching position.

[0096] Thus, the second signal generator 20 is connected to the first band port 42, the first signal generator 18 is connected to the second band port 44 and the receiver 22 is connected to the third band port 46.

[0097] Therefore, a RF signal having a carrier signal in the low-band (second carrier signal) and a carrier signal in the mid-band (first carrier signal) is fed to the device under test 14 via the measurement port 28 and the device port 16.

[0098] A response to this RF signal is input at the measurement port 28 coming from the device under test 14. The response may include RF signals in the high- band of the triplexer 24 (i.e. the frequency band of the third-band port 46) that are due to passive intermodulation (PIM) in the device under test 14.

[0099] This signal input at the measurement port 28 from the antenna under test 14 is then fed, via the third band port 46 of the triplexer 24 and the transfer switch 26 to the receiver 22.

[0100] At S4, the frequency of the second carrier signal is swept through a transmit frequency range ft wherein the frequency fi of the first carrier signal is kept constant. The relationship of the frequency bands is depicted in Figure 3.

[0101] The transmit frequency range ft may correspond to the entire frequency band of the first band port 42. It is also conceivable that the transmit frequency range ft covers only part of the frequency band of the first band port 42 of the triplexer 24.

[0102] The signal input at the measurement port 28 lies within a response frequency range frand is measured by the receiver 22 (S5). The response frequency range frlies within the frequency band of the third band port 46.

[0103] It is also conceivable to measure 3rd, 5th and 7th orders, depending on the frequency bandwidth of the triplexer.

[0104] During the measurements, the control unit 30 is configured to synchronize the first signal generator 18 and the second signal generator 20 for synchronizing the first and second carrier signals.

[0105] This may be done using transistor-transistor logic signals (TTL signals) sent from the control unit 30 to the first and second signal generators 18, 20 and / or by using a second realtime channel with reduced or no protocol overhead.

[0106] The control unit 30 receives the signal measured by the receiver 22 and determines the presence and the frequency location of PIM in the device under test 14.

[0107] For performing measurements in the frequency band of the first band port 42 of the triplexer 24, the method may continue as follows.

[0108] After the second carrier signal has been swept throughout the transmit frequency range ft, the transfer switch 26 is switched from the first switching position to the second switching position at S6, thus, swapping the connection of the second signal generator 20 and of the receiver 22 to the band ports of the triplexer 24.

[0109] Now, the second signal generator 20 is connected to the third band port 46 and the receiver 22 is connected to the first band port 42 of the triplexer 24. At S7, the second signal generator 20 is controlled to generate a second carrier signal in a second transmit frequency range fo. The second frequency range may be the entire frequency band of the third band port 46 of the triplexer 24 or only part of the frequency band of the third band port 46 of the triplexer 24.

[0110] The response frequency band fr2 lies now in the frequency band of the first band port 42 of the triplexer 24.

[0111] The first signal generator 18 still generates a carrier signal with the first frequency fi (S8).

[0112] The relationship of the frequency bands in the second switching position is depicted in Figure 4.

[0113] At S9, the signal input at the measurement port 28 is measured by the receiver 22.

[0114] It is also possible to perform measurements in the frequency band of the third band port 46 of the triplexer 24 (i.e. in the second switching position of the transfer switch 26) before performing measurements in the frequency band of the first band port 42 of the triplexer 24 (i.e. in the first switching position of the transfer switch 26). Put differently S6-S9 may be carried out before S1-S5.

[0115] Thus, using the test setup 10, the test apparatus 12, and the method, it is possible to efficiently test the device under test 14, in particular to perform PIM measurements of the device under test 14 over a broad frequency range in an automated and time-saving fashion.

[0116] Figure 5 shows a second embodiment of a test setup 10 with a second embodiment of a test apparatus 12, which substantially corresponds to the first embodiment. Thus, in the following, only the differences are discussed and the same and functionally the same components are labeled with the same reference signs. In the second embodiment, the device under test 14 has two device ports 16.

[0117] Further, the test apparatus 12 has two measurement ports 28, wherein each measurement port 28 is connected to one of the device ports 16 of the device under test 14.

[0118] The test apparatus 12 comprises two triplexers 24, two transfer switches 26 and two receivers 22. In the shown embodiment, only one first signal generator 18 and one second signal generator 20 are provided.

[0119] It is also conceivable that the test apparatus 12 comprises two first signal generators 18 and two second signal generators 20.

[0120] Each of the measurement ports 28 is associated with one triplexer 24, one transfer switch 26 and one receiver 22, wherein each receiver 22, each triplexer 24 and each transfer switch 26 are associated only with one of the measurement ports 28.

[0121] The measurement port 28, the receiver 22, the triplexer 24 and / or transfer switch 26 associated with one another are configured and connected as described with respect to the first embodiment.

[0122] In the case of two first signal generators 18 and two second signal generators 20, also each of the two first signal generators 18 and two seconds signal generators 20 is associated with one measurement port 28 and connected as described with respect to the first embodiment. In this case, for each of the measurement ports 20 an assembly as discussed in the first embodiment is provided.

[0123] In the shown second embodiment, however, the first signal generator 18 and the second signal generator 20 are connected to both measurement ports 28 via the transfer switches 26 and triplexers 24 associated with the respective ones of the measurement ports 28. To this end, the test apparatus 12 comprises power splitters 52.

[0124] The first signal generator 18 is connected to the second band port 44 of each of the triplexers 24 by the use of one power splitter 52.

[0125] Likewise, the second signal generator 20 is connected to the third switch ports 36 of the transfer switches 26 by means of a power splitter 52.

[0126] The power amplifiers 48 may be provided as discussed with respect to the first embodiment, i.e. one power amplifier 48 is associated with one of the measurement ports 28 amplifying both the first carrier signal and the second carrier signal.

[0127] For each of the measurement ports, a power amplifier 48 is provided, wherein the power amplifier 48 receives and amplifies the first carrier signal of the associated first signal generator 18 and outputs the amplified first carrier signal to the second band port 44 of the associated triplexer 24, and wherein the same respective power amplifier 48 receives and amplifies the second carrier signal of the associated second signal generator 20 and outputs the amplified second carrier signal to the third switch port 36 of the associated transfer switch 26.

[0128] For testing the device under test 14, the method as discussed with respect to the first embodiment is performed so that the first carrier signal and the second carrier signal are transmitted to both measurement ports 28 simultaneously. Thus, the generation of the first carrier signal and of the second carrier signal as well as the measurement of the signal input at the respective measurement ports 28 by the associated receiver is performed for all measurement ports of the test apparatus 12 simultaneously.

[0129] Thus, the time needed for testing the device under test 14 with multiple ports for PIM at each port is drastically reduced. Even though a test setup 10 with a device under test 14 comprising only two device ports 16 has been discussed, the device under test 14 and also the test apparatus 12 may comprise more than two device ports 16 and measurement ports 28, respectively, in particular 4, 8, 12, 16, 18 or 32.

[0130] Generally, the test apparatus 12 comprises a triplexer 24, a transfer switch 26 and a receiver 22 for each of the measurement ports 28 which are connected and configured as discussed with respect to the first embodiment.

[0131] For each of the device ports 16 having the same frequency band, respective measurement ports 28 are provided at the test apparatus 12 having also the same frequency band (as defined by the frequency band of the associated triplexer 24).

[0132] For these measurement ports 28 having the same frequency band, it is possible to provide only one first signal generator 18 and one second signal generator 20, wherein the first and second carrier signals are distributed to the various measurement ports as discussed with respect to the second embodiment.

[0133] It is conceivable, that only a subset of the measurement ports 28 having the same frequency band share the same first and second signal generator 18, 20. It is also conceivable, that for each measurement port 28 a first signal generator 18 and a second signal generator 20 are provided.

[0134] For example, for a device under test 14 having 18 device ports 16 and operating in four different frequency bands, a test apparatus 12 is provided having 18 triplexers 24, 18 transfer switches 26, and 18 receivers 22.

[0135] The test apparatus 12 may have nine power amplifiers 48, wherein the signals dedicated for the different polarizations of the same radiator array are amplified by the same power amplifier 48. Eight power splitters 52 are provided as well as four first signal generators 18 and four second signal generators 20.

[0136] Also with multiple measurement ports 28, the various first and second signal generators 18, 20 are synchronized by the control unit 30, in particular using TTL signals or a second realtime channel.

Claims

Claims1. Test apparatus for testing a device under test (14), in particular for performing PIM measurements, comprising at least one first signal generator (18), at least one second signal generator (20), at least one receiver (22), at least one triplexer (24), at least one transfer switch (26) and at least one measurement port (28) for connecting the test apparatus (12) to the device under test (14), wherein the at least one triplexer (24) is associated with one of the at least one transfer switch (26), with one of the at least one first signal generator (18), with one of the at least one second signal generator (20), with one of the at least one receiver (22), and with one of the at least one measurement port (28), wherein the at least one transfer switch (26) comprises a first switch port (32), a second switch port (34), a third switch port (36), and a fourth switch port (38), wherein the triplexer (24) comprises a common port (40) connected to the first associated measurement port (28), a first band port (42), a second band port (44), and a third band port (46), wherein the associated first signal generator (18), the associated second signal generator (20) and the associated receiver (22) are each connected to one of the first band port (42), the second band port (44), and the third band port (46) of the associated triplexer (24), partly via the associated transfer switch (26), and wherein the associated transfer switch (26) is configured to swap the connection of the associated first signal generator (18), of the associated second signal generator (20), and / or of the associated receiver (22) to one of the first band port (42), the second band port (44) and / or the third band port (46).

2. Test apparatus according to claim 1, characterized in that the transfer switch (26) has a first switching position and a second switching position, wherein, in the first switching position, the first switch port (32) is connected to the second switch port (34) and the third switch port (36) is connected to the fourth switch port (38), and in the second switching position, the first switch port (32) is connected to the fourth switch port (38) and the second switch port (34) is connected to the third switch port (36).

3. Test apparatus according to claim 1 or 2, characterized in that the first band port (42) is connected to the fourth switch port (38) of the associated transfer switch (26), the second band port (44) is connected to the associated first signal generator (18), and the third band port (46) is connected to the second switch port (34) of the associated transfer switch (26), and wherein the first switch port (32) of the associated transfer switch (26) is connected to the associated receiver (22), and the third switch port (36) of the associated transfer switch (26) is connected to the associated second signal generator (20).

4. Test apparatus according to any of the preceding claims, characterized in that the first band port (42) is a low-band port, the second band port (44) is a mid-band port, and the third band port (46) is a high-band port.

5. Test apparatus according to any of the preceding claims, characterized in that the second band port (44) has a bandwidth being less than the bandwidth of the first band port (42) and of the bandwidth of the third band port (46), in particular less than fifth, more particularly less than one tenth of the bandwidth of the first band port (42) and of the bandwidth of the third band port (46).

6. Test apparatus according to any of the preceding claims, characterized in that the second band port (44) has a bandwidth being less or equal to 20 MHz, in particular less or equal to 5 MHz, and / or that the first band port (42) has a bandwidth being greater or equal to 250 MHz, in particular greater orequal to 400 MHz, and / or that the third band port (46) has a bandwidth being greater or equal to 250 MHz, in particular greater or equal to 400 MHz.

7. Test apparatus according to any of the preceding claims, characterized in that the test apparatus (12) comprises a plurality of the measurement ports (28), in particular 4, 8, 12, 16, 18 or 32 measurement ports (28), a plurality of the triplexers (24), a plurality of the transfer switches (26) and a plurality of the receivers (22), wherein each of more than one of or each of all of the plurality of the measurement ports (28) is associated with one of the plurality of the triplexers (24), with one of the plurality of transfer switches (26) and with one of the plurality of receivers (22).

8. Test apparatus according to claim 7, characterized in that the at least one first signal generator (18) and / or the at least one second signal generator (20) is connected to more than one measurement port (28) via the transfer switches (26) and triplexers (24) associated with the respective measurement ports (28), in particular using a power splitter (52).

9. Test apparatus according to claim 8, characterized in that the test apparatus (12) comprises at least one power splitter (52) and a plurality of power amplifiers (48), wherein the at least one first signal generator (18) and / or the at least one second signal generator (20) is connected to more than one of the plurality of power amplifiers (48) via a respective power splitter (52).

10. Test apparatus according to any of the claims 7 to 9, characterized in that for each of the measurement ports (28) a power amplifier (48) is provided, wherein the power amplifier (48) receives and amplifies signals from the associated first signal generator (18) and outputs the amplified signal of the first signal generator (18), and wherein the respective power amplifier (48) receives and amplifies signals from the associated second signal generator (20) and outputs the amplified signal of the second signal generator11. Test apparatus according to any of the preceding claims, characterized in that the test apparatus (12) comprises a control unit (30), wherein the control unit (30) is configured to control the switching position of the transfer switch (26), the at least one receiver (22), the at least one first signal generator (18) and the at least one second signal generator (20).

12. Test apparatus according to claim 11, characterized in that the control unit (30) is configured to synchronize the at least one first signal generator (18) and the at least one second signal generator (20), in particular using TTL signals.

13. Test setup comprising a device under test (14) and a test apparatus (12) according to any of the preceding claims, wherein the device under test (14) is connected to the at least one measurement port (28).

14. Test setup according to claim 13, characterized in that the device under test (14) has a plurality of device ports (16) and the test apparatus (12) comprises a plurality of the measurement ports (28), in particular wherein each of the device ports (16) of the device under test (14) is connected to one of the measurement ports (28) of the test apparatus (12) and / or each of the measurement ports (28) of the test apparatus (12) is connected to one of the device ports (16) of the device under test (14).

15. Method for testing a device under test (14), in particular for performing PIM measurements, using a test apparatus (12) according to any of the claims 1 to 12 and / or a test setup (10) according to claim 13 or 14, the method comprising: generating a first carrier signal by the at least one first signal generator (18) and applying the first carrier signal to the second band port (44) of the associated triplexer (24),- generating a second carrier signal by the at least one second signal generator (20) and applying the second carrier signal to the third switch port (36) of the associated transfer switch (26),- setting the associated transfer switch (26) in the first switching position or the second switching position,- sweeping the frequency of the second carrier signal in a frequency range being the entire frequency band or part of the frequency band of the first band port (42) or the third band port (46), respectively, of the associated triplexer (24), and- measuring the signal input at the measurement port (28) by the receiver (22).

16. Method according to claim 15, characterized in that the first carrier signal has a frequency within the frequency band of the second band port (44) and / or that the frequency of the first carrier signal is kept constant.

17. Method according to claim 15 or 16, characterized in that, after sweeping the frequency of the second carrier signal in a transmit frequency range being the entire frequency band or part of the frequency band of the first band port (42) or the third band port (46), respectively, of the associated triplexer (24), the associated transfer switch (26) is switched from the first switching position to the second switching position or from the second switching position to the first switching position, respectively, and the frequency of the second carrier signal is swept in a transmit frequency range being the entire frequency band or part of the frequency band of the third band port (46) or the first band port (42), respectively, of the associated triplexer (24), and the signal input at the measurement port (28) is measured by the receiver (22).

18. Method according to any of the claims 15 to 17, characterized in that the generation of the first carrier signal and of the second carrier signal as well as the measurement of the signal input is performed for more than one, in particular all of the measurement ports (28) of the test apparatus (12) simultaneously.

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